The problem of a 98 foot tsunami hitting Japan:

 Is that if you look at a map it could also hit here on the west coast of the U.S.  too and be 45 feet tall or more after traveling across the ocean. 

So, imagine a wall of water (this is NOT a wave) in a Tsunami the whole ocean rises up and stays up for a while at this 98 or 45 foot or whatever level it reaches and goes far far inland. So, if this hits be sure to get in your car and move inland above 100 feet in elevation anywhere in California, Oregon, Washington or Alaska (British Columbia, Canada and Mexico and South America too.

Whole Islands all across the Pacific could be wiped out that aren't over 100 feet or more in altitude to begin with. Hawaii, at least on Maui and the Big Island go up (maui 10,000 feet) and big island over 14,000 feet. So, people could escape to these elevations anything above 100 feet and likely be okay.

But, if this tsunami megaquake hits you don't want to be below 100 feet in elevation anywhere on the Pacific Ocean anywhere.